The present invention relates generally to a device for preventing improper disengagement of a clutch, and more particularly it relates to a device for forcibly moving the clutch disc to a neutral position upon disengagement of the clutch to release the clutch facings from the friction surfaces of both the flywheel and pressure plate and thereby prevent improper disengagement of the clutch.
Generally, the spline hub of a clutch disc is splined to a main drive shaft for rotation therewith so that when the clutch is engaged or disengaged the clutch disc is movable in its axial direction. Thus with this type of clutch, the spline hub must be smoothly movable on the main drive shaft in the axial direction every time the clutch is engaged or disengaged.
However, the splined portion is subject directly or indirectly to resonance caused by high speed rotation of the main drive shaft or to small vibration due to high speed driving of a motor vehicle to undergo oxidation or wear, or a foreign matter may get in the splined portion, thereby impeding the movement of the spline hub.
Moreover, heat generation or the like, caused by the sliding friction between the clutch facings and the friction surfaces of the flywheel and the pressure plate, will give rise to sticking contact between the facings and the friction surfaces to likewise hinder the aforementioned movement of the clutch disc.
If the movement of the clutch disc to a neutral position is thus impeded when the clutch is disengaged, there arises stick slippage or the like between the clutch facing and the friction surface of the flywheel, making it impossible to effect complete separation in spite of the disengagement of the clutch, which for instance will seriously affect a speed changing operation and markedly reduce the life of the clutch facing.